Has global warming changed your gardening?

[Guest]

I think global warming has changed the plants that we, here, can grow, but the levels we are seeing are not out of line with anything that has happened before.

For us, in Chalk, and North West Kent, the biggest indication is the dramatic rise in height of cordylines. The normal cut to ground temperature is around -9C. Over the last 12 or so years, cordylines have not been cut back.

Also self sown seedlings of exotics are on the increase. We have:

Trachycarpus seedlings from 1997.
Spider plants surviving outside from 2000
Dicksonia squarosa spores growing from 2001
Cordyline seedlings from 2002
Canna indica seedlings from 2004
Phormium seedlings from 2004
Tradescathia (wandering jew) survived outside from 2004
Petunia seedlings ( overwintered outside)sprouted from May 2005
Bizzy Lizzy 2005/6.

Our summers are becoming dryer, making water a big problem, as our rainfall rate doesn't keep up with evaporation. If a drought order is imposed, as threatened, my garden would change dramatically. Gone would be the bananas, colocasias, cannas, ferns etc. Replaced by Herbs like Rosemarry, lavender, etc. I would also have to dig out the alluvial clay and replace with better drained soil to accomodate succulents. Basically, winter cold wouldn't be the limiting factor, it would be the summer drought.

How are you affected? I notice Scotland seems to be getting plenty of rain. Is there more recently? I also notice there are more torrential thunderstorms recently, but not here. Do these flatten your plants, or wash them away?

Best regards
Dave

[Dave Brown]

Canna Indica started out flowering in late August in 1981 having been left in the ground over winter. Now, in 2006 the flowering season is from late june to the frosts in November, or sometimes December.

In the first years the plants did not ripen any seed, but now they self seed (Indian shot bullets) everywhere. From 2004 they started to germinate the next year. These are where the ground stays moist ie under the gravel (propagation unit) commonly called, my drive, and between paving slabs on my patio.

[turtile]

http://www.delawareonline.com/apps/pbcs ... 6609150373

The lowest temperature we've had last year was 21F (-6C). We didn't have any snow. We're rated Zone 7a(0-5F).

[Dave Brown]

Hi Turtile,

Yes, it seems the winter lows are the most dramatic change. As I said Cordylines now don't get killed off to ground level as they used to. I think the soil temperature remains higher protecting seed from too much frost, and they germinate the next spring/summer. We haven't had a -10C (14F) for over 14 years now. When I first moved to Chalk, we got a -10C at least every 2 or 3 years and the Cordylines did not get above about 4 feet before being cut down again. My Cassey is now 18 feet and still growing a couple of feet a year.

It isn't all up side though. I had the pernacious little weed called oxalis with bright yellow flowers and a deep tap root, which was a real pain in the greenhouse and conservatory. Now it is a real pain anywhere with dry soil in the garden. I've had to spray it this year as it took over my gravel drive. Another problem is mealy bugs, or wooly aphids. They attack my phormiums by summer, but don't get killed off by the winter now. So I have to treat them.

I'm just waiting for real nasties to arrive. With many Austrailian plants surviving here now, so may the forna. I had a funnel Web on one of my trachys. Not big enough to be the Australian Funnel Web Spider, but I don't know of a British spider that does that, so I treated it with caution.

My official temperature in the shade on the north side of the building is showing 21.6C at the moment, but the shade temp on the decking, where I am writing this, to the south side is 26C this extends summer to early October, and the first frost can be as early as late October or as late as January.

Cheers
Dave.

[Dave Brown]

Once again, the impossible seems to happen. A couple of posts ago I said Petunia seed was overwintering and sprouting in late spring. I now have a Petunia which survived over winter, although not exposed to radiation frost as under the edge of a Spinning Gum, and has put on a spurt of growth recently. Finally about a week ago I noticed it was in flower for a second year.

It seems to fit in with the chippings